2.9BSD - /usr/src/cmd/pwd.c

   1: /*
   2:  * Print working (current) directory
   3:  */
   4: #include    <stdio.h>
   5: #include    <sys/param.h>
   6: #include    <sys/stat.h>
   7: #include    <sys/dir.h>
   8: #include    <sys/file.h>
   9: 
  10: char    dot[]   = ".";
  11: char    dotdot[] = "..";
  12: char    name[512];
  13: int file;
  14: int off = -1;
  15: struct  stat    d, dd;
  16: struct  direct  dir;
  17: 
  18: main()
  19: {
  20:     int rdev, rino;
  21: 
  22:     stat("/", &d);
  23:     rdev = d.st_dev;
  24:     rino = d.st_ino;
  25:     for (;;) {
  26:         stat(dot, &d);
  27:         if (d.st_ino==rino && d.st_dev==rdev)
  28:             prname();
  29:         if ((file = open(dotdot, FATT_RDONLY)) < 0) {
  30:             perror(dotdot);
  31:             exit(1);
  32:         }
  33:         fstat(file, &dd);
  34:         if (chdir(dotdot) < 0) {
  35:             perror(dotdot);
  36:             exit(1);
  37:         }
  38:         if(d.st_dev == dd.st_dev) {
  39:             if(d.st_ino == dd.st_ino)
  40:                 prname();
  41:             do
  42:                 if (read(file, (char *)&dir, sizeof(dir)) < sizeof(dir)) {
  43:                     perror("read: ..: ");
  44:                     exit(1);
  45:                 }
  46:             while (dir.d_ino != d.st_ino);
  47:         }
  48:         else do {
  49:                 if(read(file, (char *)&dir, sizeof(dir)) < sizeof(dir)) {
  50:                     perror("read: ..: ");
  51:                     exit(1);
  52:                 }
  53:                 stat(dir.d_name, &dd);
  54:             } while(dd.st_ino != d.st_ino || dd.st_dev != d.st_dev);
  55:         close(file);
  56:         cat();
  57:     }
  58: }
  59: 
  60: prname()
  61: {
  62:     write(1, "/", 1);
  63:     if (off<0)
  64:         off = 0;
  65:     name[off] = '\n';
  66:     write(1, name, off+1);
  67:     exit(0);
  68: }
  69: 
  70: cat()
  71: {
  72:     register i, j;
  73: 
  74:     i = -1;
  75:     while (dir.d_name[++i] != 0);
  76:     if ((off+i+2) > sizeof (name) - 1)
  77:         prname();
  78:     for(j=off+1; j>=0; --j)
  79:         name[j+i+1] = name[j];
  80:     off=i+off+1;
  81:     name[i] = '/';
  82:     for(--i; i>=0; --i)
  83:         name[i] = dir.d_name[i];
  84: }

Defined functions

Defined variables